Is Your Face Mask Really Safe?
A new study reveals a potential problem with cloth face coverings and underlines the importance of handling as well as washing your face covering carefully before and after using.
Face Masks Do Work
A new study performed by researchers at the University of California, Davis, testing surgical masks, N95 masks, and other types of face coverings including homemade cotton coverings, shows that there may be some caveats when deciding on whether to go with a commercial professional style mask or a homemade cloth mask.
The Centers for Disease Control and Prevention, and the World Health Organization both endorse the use of homemade masks as acceptable alternatives to surgical masks and N95 respirators due to that the demand for commercial masks continues to outnumber the available supply.
The primary point of wearing face coverings is to prevent asymptomatic people who are infected with COVID-19 from transmitting the virus to others via airborne transmission. Earlier studies have shown that many types of face coverings do reduce the spread of airborne particles, but according to this latest study, little has been published on how well the different masks and coverings compare in their effectiveness against each other.
A news release from UC Davis reports that experiments were designed to measure the flow of particles from volunteers wearing masks while they performed “expiratory activities” such as breathing, talking, coughing and moving their jaw as if chewing gum, while sitting in front of a funnel in a laminar flow cabinet as shown in the accompanying photo of this article.
“The funnel drew air from in front of their faces into a device that measured the size and number of particles exhaled. They wore either no mask, a medical-grade surgical mask, two types of N95 mask (vented or not), a homemade paper mask or homemade one- or two-layer cloth mask made from a cotton T-shirt according to CDC directions,” explains the news release.
Note, that the particles counted are not viral-related, but the normal moisture and the like that comes out whenever someone opens their mouth.
However, Cloth Face Coverings Might Not Be So Safe
What the researchers found was that all of the masks do a fairly good job of significantly reducing the amount of particles coming out of the test subjects mouths and passing through the mask material. However, what they also found was that the homemade cloth coverings appear to release a significant amount of particles measured—even more so than when not wearing a covering at all over the mouth.
The cloth masks were both single and double-layer coverings made from new cotton t-shirts (Calvin Klein Men’s Liquid Cotton Polo, 100% cotton), worn and tested by the study participants using the funneled particle measuring equipment.
When the cloth masks were compared against each other using non-laundered versus laundered cotton material, both types still released a significant amount of particles, which the researchers attribute to as likely being primarily fibers from the fabrics.
In their published paper, the researchers noted that, “Our work does raise the possibility, however, that virus-contaminated masks could release aerosolized fomites into the air by shedding fiber particulates from the mask fabric. Since mask efficacy experiments are typically only conducted with fresh, not used, masks, future work assessing emission of viable pathogens should consider this possibility in more detail.”
The researchers added that their findings, “…raises questions about whether homemade masks using other fabrics, such as polyester, might be more efficient than cotton in terms of blocking expiratory particles while minimizing shedding of fabric particulates, and whether repeated washings might affect homemade masks.”
The conclusion they reached about these homemade cloth style coverings and masks is that as a precaution, users of homemade fabric masks should take care on how they handle the mask as they put them on and remove them repeatedly and that individuals should, “…wash or otherwise sterilize them on a regular basis to minimize the possibility of emission of aerosolized fomites.”
Why This Matters
For a real-world example of why being especially careful with fiber emitting cloth masks might be so important, suppose someone wears a homemade cloth mask and has the habit of storing it in their car’s sun visor. If the person is asymptomatic, but releases viral particles that are trapped in the cotton fabric, imagine the potential viral fall of particles directly onto a non-infected family member’s face who borrows the car after he or she flips the sun visor down.
Timothy Boyer has a Ph.D. in Molecular and Cellular Biology from the University of Arizona. For 20+ years he has been employed as a freelance health and science writer. Today, with an eye on the latest news, Timothy continues writing about science with a focus on what you need to know for healthier living. For continual updates about health, you can also follow Timothy on Twitter at TimBoyerWrites.
Image Source: Courtesy of Christopher Cappa, UC Davis; “Comparing Face Coverings in Controlling Expired Particles Surgical, N95 Masks Block Most Particles (IMAGE)”
“Comparing Face Coverings in Controlling Expired Particles” UC Davis News, Sept. 24, 2020.
“Efficacy of masks and face coverings in controlling outward aerosol particle emission from expiratory activities” Sima Asadi et al., Scientific Reports 10, Article number: 15665 (2020.)